An array is monotonic if it is either monotone increasing or monotone decreasing.
An array A is monotone increasing if for all i <= j, A[i] <= A[j]. An array A is monotone decreasing if for all i <= j, A[i] >= A[j].
Return true if and only if the given array A is monotonic.
Example 1:
Input: [1,2,2,3] Output: true
Example 2:
Input: [6,5,4,4] Output: true
Example 3:
Input: [1,3,2] Output: false
Example 4:
Input: [1,2,4,5] Output: true
Example 5:
Input: [1,1,1] Output: true
Note:
1 <= A.length <= 50000-100000 <= A[i] <= 100000struct Solution;
impl Solution {
fn is_monotonic(a: Vec<i32>) -> bool {
let mut increasing = true;
let mut decreasing = true;
let n = a.len();
for i in 1..n {
if a[i] > a[i - 1] {
decreasing = false;
}
if a[i] < a[i - 1] {
increasing = false;
}
}
increasing || decreasing
}
}
#[test]
fn test() {
let a = vec![1, 2, 2, 3];
assert_eq!(Solution::is_monotonic(a), true);
let a = vec![6, 5, 4, 4];
assert_eq!(Solution::is_monotonic(a), true);
let a = vec![1, 3, 2];
assert_eq!(Solution::is_monotonic(a), false);
let a = vec![1, 2, 4, 5];
assert_eq!(Solution::is_monotonic(a), true);
let a = vec![1, 1, 1];
assert_eq!(Solution::is_monotonic(a), true);
}